Webasto Hydronic Heater Thermo 90

[prajna101]

I am having issues with my Webasto hydronic heater. Its a Thermo 90. I was replacing the burn tube and in the process I broke the flame sensor. I ordered a replacement and installed it. Install seems pretty straight forward, but I am getting a fault of 5 flashes. That is either wiring, or the flame sensor. I removed the flame sensor and tested it with my multi meter. I get a reading of 3.4 ohms which is within range. So that seems to test ok. I removed the wiring pins and reinstalled. I tried reversing the wires to the pins (they are both grey). I have taken it apart and put it back together a couple of time in the process and no matter what I get five flashes on the warning light. I am running out of ideas on what to test. Any thoughts?

[tkeithlu]

I'm sorry that you have not received a knowledgeable reply. It will take someone with very specific knowledge, I think.

It's a very long shot, because getting a defective part happens, but not often, but put a propane torch to the flame sensor and see that the resistance changes.

What does customer support say about the five flashes? Is that a coded error?

Is there voltage coming to the flame sensor?

Sorry I can't do better.

[Manateeman]

Five flashes is not the code. It’s the flashes after the five flashes. I remember something about the unit locking you out after so many tries.
Anything on line ? I’ll see if I can find more.
What else is on the tag.
Happy
Trails to you. Mark and his sleeping manatees

[Manateeman]

Hi. The workshop manual is online at Sure Marine Services and Butler Technik.
Butler Technik has a big web site and are very helpful .
You don’t need the stuff to link a computer to your heater .
Check every wire connection. What timer do you have.
The trouble shooting section tells you how to test parts.
Please let me know how it goes.
Happy trails to you.
Captain Mark and his warm but bad breath manatees